1 00:00:00,520 --> 00:00:02,930 It's also a single broadcast domain. 2 00:00:02,950 --> 00:00:10,390 In other words, if a device like A sends a broadcast, everyone in the network would receive that broadcast 3 00:00:10,390 --> 00:00:13,090 and would need to process the broadcast. 4 00:00:13,390 --> 00:00:16,860 When a device receives a broadcast, it will process it. 5 00:00:16,870 --> 00:00:22,690 In other words, it will receive it on the network interface card and then forward it to upper layers 6 00:00:22,690 --> 00:00:24,190 in the OCI model. 7 00:00:24,190 --> 00:00:31,600 So as an example, the CPU or central processing unit of a PC would be interrupted when a PC receives 8 00:00:31,600 --> 00:00:32,650 the broadcast. 9 00:00:32,650 --> 00:00:40,240 So if device A starts jabbering, in other words, starts sending many, many broadcasts onto the network, 10 00:00:40,240 --> 00:00:46,120 those broadcasts would be received by all the devices in the network, and every device would be interrupted 11 00:00:46,120 --> 00:00:53,560 and would have to process the broadcast so the CPUs of every PC would be interrupted by every broadcast 12 00:00:53,560 --> 00:00:59,110 sent by A and would need to process that broadcast if A was sending a broadcast. 13 00:00:59,110 --> 00:01:05,290 But the traffic was only intended for B, both C and D would still have to receive that broadcast process 14 00:01:05,290 --> 00:01:06,520 it and drop it. 15 00:01:06,760 --> 00:01:12,970 But the problem is they CPUs were interrupted, which may cause the PC to slow down. 16 00:01:12,970 --> 00:01:19,930 Thus, because of the issues with regards to maximum segment length, maximum hosts on a segment and 17 00:01:19,930 --> 00:01:26,830 cable breaks, ten based two was replaced with ten base T ten base RT uses unshielded twisted pair. 18 00:01:26,860 --> 00:01:32,200 It's very unlikely that you're going to encounter ten base two in today's networks. 19 00:01:32,290 --> 00:01:40,240 So ten base T or twisted pair Ethernet refers to the use of cable that contains insulated copper wires 20 00:01:40,240 --> 00:01:44,680 twisted together in pairs with a maximum distance of 100 meters. 21 00:01:44,890 --> 00:01:51,730 The cable is a lot thinner and more flexible than coaxial cable, which was used in both ten base two 22 00:01:51,730 --> 00:01:53,830 and ten base five networks. 23 00:01:53,950 --> 00:02:01,570 In ten t we tend to use unshielded twisted pair cables, shielded twisted peg cables may be used in 24 00:02:01,570 --> 00:02:08,350 noisy environments where there's a shield around each pair of wires, plus an overall shield around 25 00:02:08,350 --> 00:02:13,720 the cables to protect them against excessive electrical magnetic interference. 26 00:02:13,840 --> 00:02:21,010 This may be caused, as an example, where network cables are close to electrical cables, so additional 27 00:02:21,010 --> 00:02:22,510 protection is required. 28 00:02:22,510 --> 00:02:29,350 But most networks tend to use unshielded twisted pair where the cables are not shielded against interference 29 00:02:29,350 --> 00:02:30,340 in the same way. 30 00:02:30,760 --> 00:02:37,660 Once again, ten base t means ten megabits per second base means base band rather than broadband. 31 00:02:37,840 --> 00:02:42,220 T means twisted pair with a maximum segment size of 100 meters. 32 00:02:42,550 --> 00:02:50,230 The connectors used are j 45 connectors as seen here, and you've probably connected an RJ 45 connector 33 00:02:50,230 --> 00:02:52,900 to your PC many times in the past. 34 00:02:54,060 --> 00:03:01,770 Unshielded twisted pair or UTP, is a set of four pairs of wires with each wire in a pair being twisted 35 00:03:01,770 --> 00:03:05,520 around the other to prevent electromagnetic interference. 36 00:03:05,700 --> 00:03:10,410 As an example, notice here we have a twisted pair for pairs. 37 00:03:10,410 --> 00:03:13,500 Make up the UTP used in Ethernet. 38 00:03:13,530 --> 00:03:20,190 Each wire has a color coded plastic insulation and the wires are inside and out a jacket. 39 00:03:20,430 --> 00:03:25,170 In an Ethernet environment, the Y is connected to an RJ 45 connector. 40 00:03:25,200 --> 00:03:33,210 As shown here, the advantage of UTP or Untrusted Pair is it's a less expensive and easier to install 41 00:03:33,240 --> 00:03:38,400 than other cabling implementations such as shielded, twisted pair or coaxial cable. 42 00:03:38,400 --> 00:03:42,300 There are various categories of UTP, which I'll talk about in a moment. 43 00:03:42,420 --> 00:03:48,810 The maximum distance is 100 meters without the use of a signal regeneration device such as a hub or 44 00:03:48,810 --> 00:03:49,440 switch. 45 00:03:49,680 --> 00:03:56,070 So this is the type of cabling you'll probably encounter many, many times in your networking career. 46 00:03:56,580 --> 00:03:59,430 UTP uses RJ 45 connectors. 47 00:03:59,430 --> 00:04:03,690 So let's talk about the PIN positions on an RJ 45 connector. 48 00:04:03,990 --> 00:04:10,980 There are two main implementations which are RT five, six, eight, A and RT five, six, eight B and 49 00:04:10,980 --> 00:04:15,000 there's a slight difference with the pairing of cabling in each implementation. 50 00:04:15,180 --> 00:04:23,130 Tia EIA 568 was developed to define standards for telecommunications cabling systems. 51 00:04:23,490 --> 00:04:29,370 EIA is the Electronic Industry Alliance and is a standards based organization. 52 00:04:29,490 --> 00:04:36,150 Tia EIA 568c attempts to define structured cabling standards. 53 00:04:36,480 --> 00:04:39,930 So the difference between A and B is the pairing of cabling. 54 00:04:39,930 --> 00:04:48,060 Notice in a white green stripe and green solid are connected to pins one and two, whereas in B, white 55 00:04:48,060 --> 00:04:52,140 orange stripe and solid orange are connected to one and two. 56 00:04:52,620 --> 00:04:58,290 So they are subtle differences between the cabling of orange and green in five, six, eight, A and 57 00:04:58,290 --> 00:04:59,430 five, six, eight B. 58 00:04:59,430 --> 00:05:05,850 Now this will make no difference as both configurations wire the pin straight through. 59 00:05:06,300 --> 00:05:11,970 In other words, pin one goes to pin one on both sides of the cable, pin two goes to pin two and so 60 00:05:11,970 --> 00:05:13,020 forth and so on. 61 00:05:13,290 --> 00:05:19,800 So notice on pin one, it's white, green in five, six, eight, a but is white orange in five, six, 62 00:05:19,800 --> 00:05:25,980 eight B The most popular implementation tends to be B, but it will make no difference which one is 63 00:05:25,980 --> 00:05:29,400 used as long as both sides are connected straight through. 64 00:05:29,820 --> 00:05:34,920 Now you could purchase pre-made cables or you may decide to crimp your own cables. 65 00:05:35,070 --> 00:05:40,980 Pre-made cables tend to be more expensive, but have the advantage that they've been tested as well 66 00:05:40,980 --> 00:05:43,830 as the advantage that you don't have to make them yourself. 67 00:05:43,830 --> 00:05:49,500 Crimping cables yourself is cheaper and you can make your cables for the lengths that you require. 68 00:05:49,650 --> 00:05:56,280 When crimping your own cables, you need to separate each individual colored wire in the right order 69 00:05:56,280 --> 00:06:02,070 and then stick each colored wire into the appropriate slot on the RJ 45 connector. 70 00:06:02,100 --> 00:06:04,920 You then use a crimping tool to crimp the wire. 71 00:06:04,920 --> 00:06:10,710 And finally, don't forget to make sure that you test your cable to ensure that you've crimped it correctly. 72 00:06:11,070 --> 00:06:16,590 A straight through cable is a type of twisted pair copper cable, which you're going to find very often 73 00:06:16,590 --> 00:06:21,660 in local area networks or lands in a standard straight through cable. 74 00:06:21,660 --> 00:06:28,470 Each pin of the connector on one end is connected to the corresponding pin on the other connector. 75 00:06:28,620 --> 00:06:32,370 In other words, pin one on the MDI device. 76 00:06:32,370 --> 00:06:40,380 In this case, a PC is connected to PIN one on an MDI device, which in this case is a hub. 77 00:06:40,740 --> 00:06:46,380 PIN two connects to pin, to pin three, to pin three and so forth and so on. 78 00:06:46,800 --> 00:06:54,510 MDI or media independent interface is an Ethernet port connection typically used on network interface 79 00:06:54,510 --> 00:06:57,240 cards or NICS of PCs. 80 00:06:57,540 --> 00:07:05,760 MDI is also used by routers and can be used on uplink ports, on Ethernet switches, on certain older 81 00:07:05,760 --> 00:07:06,570 switches. 82 00:07:06,570 --> 00:07:12,870 You'll see a button normally on the uplink port that allows you to change how that port operates so 83 00:07:12,870 --> 00:07:16,860 you can change the mode from MDI to MDI or back again. 84 00:07:16,890 --> 00:07:22,560 This allows you to connect to one switch to another switch using a straight through cable rather than 85 00:07:22,560 --> 00:07:25,890 using a crossover cable, which I'll mention in a moment. 86 00:07:26,370 --> 00:07:32,550 So in the past, you may have connected your PC to a hub such as these two using a straight through 87 00:07:32,550 --> 00:07:33,240 cable. 88 00:07:33,450 --> 00:07:39,840 Now, straight through cables are used in situations where you connect a PC to a switch or a PC to a 89 00:07:39,840 --> 00:07:42,210 bridge or a PC to a hub. 90 00:07:42,240 --> 00:07:46,860 I'm going to explain how these devices work in a moment and the differences between a hub bridge and 91 00:07:46,860 --> 00:07:47,490 switch. 92 00:07:47,580 --> 00:07:53,160 But from a cabling point of view, you would use a straight through cable from your PC to one of these 93 00:07:53,160 --> 00:07:53,370 devices. 94 00:07:53,430 --> 00:08:00,890 PCs in the past when connecting devices of the same type, such as two PCs or two routers, a crossover 95 00:08:00,890 --> 00:08:02,240 cable would be used. 96 00:08:02,600 --> 00:08:06,950 So in this case, rather than the pins being straight, they crossed. 97 00:08:07,400 --> 00:08:10,370 So in this example, we have two MDI devices. 98 00:08:10,400 --> 00:08:16,490 In other words, two PCs which need to communicate and thus a crossover cable would be required. 99 00:08:16,550 --> 00:08:20,810 This is an example for ten based or 100 based ATX. 100 00:08:21,200 --> 00:08:26,300 In this example, pins four, five, seven and eight are not used. 101 00:08:26,600 --> 00:08:29,870 But notice pin one is crossed with pin three. 102 00:08:30,170 --> 00:08:37,850 PIN two with pin six, pin three with pin one and pin six with pin two. 103 00:08:38,059 --> 00:08:47,870 In other words, the T-x or transmit and RCS or receive are correctly cabled so that TCS X plus is connected 104 00:08:47,870 --> 00:08:51,050 to Orix plus and so forth and so on. 105 00:08:51,200 --> 00:08:57,770 Pins four, five, seven and eight are configured in the straight through format but are unused in this 106 00:08:57,770 --> 00:08:58,490 example.